Pulp centrifuge



July 7, 1964 T L, JR 3,140,258

PULP CENTRIFUGE Filed Feb. 5, 1961 2 Sheets-Sheet 2 INVENTOR. [corp Aaezvaoszzz de a; wjiar TORNEYS.

United States Patent 3,140,258 PULP CENTRIFUGE Lloyd Hornbostel, Jr., Beloit, Wis., assignor to Beloit Iron Works, Beloit, Wis., a corporationof Wisconsin Filed Feb. 3, 1961, Ser. No. 86,896 2 Claims. (Cl. 210112) This invention relates to pulp drying, and more particularly to a means for continuous drying of pulp by centrifuge structure such as to release the pulp at intervals without disrupting operation of the device.

Heretofore pulp thickening and drying has generally been accomplished on a wet lap machine. However, this procedure is relatively slow and requires one or more men to operate the unit. Again, pressing the pulp by means of a screw operating inside a screen, with automatic feed and pneumatic removal of the pulp, has been used for pulp drying purposes; and while this procedure is more effective, close tolerances are required and the equipment is relatively complex.

The present invention affords a means of drying pulp which may be operated continuously, and which produces a more desirable quality in the dried pulp with lower operating costs and increased speed. The dryer includes a foraminous basket mounted on a rotating shaft which may be disposed horizontally and provides a conduit for feeding pulp into the basket. The shaft includes radial outlets for discharging the pulp onto the face of the basket, and the basket is provided with hinged sides which are normally held in closed position by cable means or the like but are releasable by centrifugal force so as to open and fling the dried pulp onto a collector structure. The cable means may be secured on a slidable collar actuated by suitable reciprocating means; and in the open position thereof the sides of the basket may be exposed to a spray of air or the like to remove the remaining pulp which adheres thereto. Thereupon, the cable means may close the hinged sides to position them to accept another charge of pulp, and it will be seen, therefore, that the operation may be continuous.

Accordingly, it is an object of the present invention to provide a centrifuge for drying pulp.

Another object of the invention is to provide pulp drying means which may be operated continuously and without the need for starting and stopping machinery and the consequent high power costs.

Another object of the invention is to provide a pulp drying means which affords automatic removal of the dried pulp or cake without the need for a dump bucket or the like.

Another object of the invention is to provide a centrifuge for drying pulp which removes liquid from the pulp more effectively than has been possible with previously available devices.

Another object of the invention is to provide a pulp drying means which does not knot the pulp as occurred with various previously available pulp drying machines.

Another object of the invention is to provide a pulp drying machine which eliminates the need for several skilled workmen to control the drying operation, and which operates substantially automatically.

Other objects and advantages will become apparent 3,149,258 Patented July 7, 1964 as the description proceeds in accordance with the drawings in which:

FIGURE 1 is a vertical sectional view of a pulp drying machine according to the present invention;

FIGURE 2 is a somewhat enlarged end view taken along the lines IIII of FIGURE 1;

FIGURE 3 is a View corresponding to the view of FIGURE 1 showing the pulp drying machine in pulp releasing position; and

FIGURE 4 is an enlarged fragmentary view of the basket structure shown in FIGURE 1.

Referring now to the drawings, the pulp drying machine of the invention is generally designated by reference numeral 10 and includes a foraminous basket 12 having sides 14 hinged to a base 16 by hinges 18. The basket 12 rotates on a shaft 20 to which the base 16 is fixedly secured, and pulp to be dried is fed through the shaft 20 from a pulp inlet 22 and a slip joint 24 communicating with a bore 26 in the shaft 20. A plurality of tubes or pulp shower elements 28 radiate from the shaft 20 in communication with the bore 26 and within the confines of the basket 12, as hereinafter further described, to discharge the pulp from the bore 26 onto the face of the basket 12 by centrifugal force. For controlling the opening and closing of the sides 14 of the basket, cables 30 are attached to the free ends of the sides and to a cable yoke 32 slidable on the outer end of the shaft 20 as actuated by reciprocable means such as the dump carriage 34. Thus the sides 14 are flung open by centrifugal force as the cable yoke 32 is moved along the shaft 20 to the position shown in FIGURE 3, the sides 14 being supported on a radial end wall 35 in the closed condition of the basket and being held by the cables 30 in the open position of FIGURE 3 with the cables engaging the wall 35. As the sides 14 are flung outwardly by centrifugal force, the cake of pulp is released therefrom to a collector or deflector ring generally indicated by reference numeral 36, which may be of any suitable type for ready removal of the pulp. Alternatively, for example, a saveall pan ring may be used as shown in dot and dash in FIGURE 3 and indicated by reference numeral 37.

The shaft 20 may be supported by journal bearings 38 and 40 for rotation by pulley and belt means 42 and 44- or otherwise, and effects the rotation of the basket 12 therewith so that in the position of FIGURE 1 and FIGURE 2 the pulp which is discharged from the conduit 26 and the pipes 28 will be pressed against the sides of the basket 14 which in their closed position are at a relatively acute angle with respect to the axis of the shaft. Thereby, fluid is expressed from the pulp and passed through the sides 14 by the centrifugal force described.

Preferably, as seen in FIGURE 4, the sides 14 include an outer plate of metal or the like 46 with perforations 48 therethrough, and an inner screen 50 secured in any suitable manner to the plate 46, to provide both strength and an effective straining of the fluid expressed there through.

Desirably also, the pipes 28 terminate at a relatively uniform distance from the sides 14 in the closed position of the sides shown in FIGURE 1, so that they are stepped upwardly in a tapering axially spaced alignment from the base 16 of the basket to assure the effective transfer of the pulp therefrom to the sides of the basket.

correspondingly, the sides have a generally trapezoidal configuration of frusto-conical type, so that when disposed against the peripherally hexagonal forward wall 32 they may rest thereagainst in mutually abutting engagement along their side edges to retain the pulp in the basket. For this purpose, of course, the said side edges will desirably be bevelled for mating engagement at such time. However, it will be understood that other shapes and configurations for the sides and basket may be encompassed within the scope of the invention.

The actuating means for moving the cable yoke 32 reciprocably and axially along the shaft 20 may include a carriage 52 having truck wheels 54 riding on rails 56, and a motor 58 on the carriage for driving a chain 60 entrained on a gear 62 on the motor shaft and on a gear (not shown) on one of the wheels 54, the motor being controlled in any suitable manner as understood by those skilled in the art.

An upstanding yoke shaft 63 is mounted by brackets or buttresses 64- on the bed of the carriage 52 in the example shown, and is provided with a preferably bifurcated upper end 66 received in mating engagement in a recess 68 in a forwardly extending portion 70 of the yoke 32, the bifurcated portion 66 journalling a reduced portion 71 of the extension 70 by suitable means such as hearings or the like (not shown) and the yoke 32 being corotatable with the shaft 20 by means of splines or the like (not shown), although other means for mounting the yoke 32 may be provided, as for example, the extension 70 may be held against rotation by the upstanding member 63 and in journalled relation to the flange portions 72 of the yoke 32 which retains the cables 30.

In order to prepare the basket 12 for a further centn' fuging operation after the pulp has been substantially removed by the outward movement of the sides 14 as above described, a shower structure 74 may be positioned in parallel to the plates 14 at their outermost extension as shown in FIGURE 3. The shower structure 74 may be of any suitable type such as an air shower through which compressed air is fed by means of a conduit 76 supporting a manifold 78 having outlet orifices for directing air under pressure through the sides 14 as they are rotated therepast in contiguous relationship. Thus, when the dump carriage 52 is retracted, and the sides 14 brought into abutting relationship with one another and against the front wall 32, pulp may again be fed through the conduit 22, the bore 26, and radially outwardly through the pipes 28 to build up a cake on the inner surfaces of the sides 14 which are formed by the screws 50.

An abutment 80 may be provided at the end of the track 56 to serve as a stop for the outward retracting movement of the carriage 52; and it will be seen that the cables will be held taut by the engagement of the wheels 54 and track 56 during the supply and centrifuging phase of the operation.

Accordingly, the shaft 20 and the basket may be rotated continuously throughout successive pulp drying opera tions, so that there is no excessive drain on power from starting and stopping as is the case with previous available devices. Furthermore, no pumps or bucket means are required to remove the material from the basket, thereby affording a further savings in power and a reduction in labor costs. And because the fluid removal action is entirely centrifugal, the pulp is not altered structurally or chemically and it does not knot, as occurs with screwoperated drying means.

As an example of a drying operation which has been carried out with the centrifuge of the invention, a 2% slurry was fed into the basket 12, which was rotated at a maximum speed of 1500 rpm. A one inch thick cylinder or cone of pulp having been formed in the basket, approximately one-half minute was required to achieve a 38% consistency in the pulp. That is, of course, a rate which is variable with freeness, and it will be understood that a layer of pulp of 2.5 inches or more will have a slower rate of drying. However, with the procedure indicated, the resultant cake had a consistency well above 40% and well above that produced by current methods, when a centrifuging operation of somewhat longer time interval was utilized. Nevertheless, it will be seen that an extremely efficient method of drying which affords large scale production efiiciencies is achieved with the device of the invention.

The cables 30 may be attached to the mid-point of the outer edges of the sides 14 in any suitable manner so as to afford a balance of forces on the sides 14. The cables should also be relatively resistant to tension forces, since, where a combined basket and cake weight of 1,000 pounds occurs, the maximum force on the cables will be 1,200 pounds, with the maximum force on the hinges 18 in their open position being 2,300 pounds and in their closed position being 800 pounds.

It will, however, be understood that other linkage means than cables may be utilized within the scope of the invention and that other mechanical means may be employed for opening and shutting the sides of the baskets for dumping the centrifuged pulp without interrupting the operation and with no need for starts and stops.

Although I have herein set forth and described my invention with respect to certain specific principles and details thereof, it will be understood by those skilled in the art that these may be varied without departing from the spirit and scope of the invention as set forth in the hereunto appended claims.

I claim as my invention:

1. A pulp drying device comprising a rotatably mounted shaft, a basket having a base fixedly mounted on said shaft and a plurality of fluid-permeable sides pivoted on said base, a linkage element connected to a free end of each of said sides and a yoke slidably mounted on said shaft and fixed against relative rotation thereto and connected to said linkage elements and a power-operated carriage having means engaging said yoke in journalled relation and guide means for said carriage to guide said carriage reciprocably to move said yoke for successively opening said sides by a given centrifugal force to release dried materials from said basket and closing said sides against said given centrifugal force to prepare the basket to receive materials to be dried by centrifuging fluid therefrom through said sides.

2. A pulp drying device comprising a rotatable shaft having a pulp inlet conduit extending partially therethrough, a basket axially mounted on said shaft and including a base fixedly mounted on the shaft and extending perpendicularly to the shaft, a plurality of fluidpermeable sides and hinge means for pivotally mounting said sides about the periphery of said base, a wall fixedly mounted on the shaft and spaced axially of said base and extending parallel thereto, said wall extending radially outwardly of said shaft further than said base, a plurality of pipes extending radially outwardly from said shaft in axially spaced relation along said shaft between said base and said wall and in communication with said conduit, a yoke slidably mounted on said shaft, cable means connected at one end thereof to said yoke and at the other end thereof respectively to the free ends of said sides for moving the free ends of said sides into abutment with the outer periphery of said wall for closing the basket, said pipes having their ends aligned at an angle substantially corresponding to the angle of inclination of said basket sides when said sides are in a closed position and said pipes being arranged in angularly offset sets with each set being disposed in longitudinally normal, bisecting relationship to a corresponding basket side, a power operated carriage engaging said yoke for moving said yoke axially on said shaft for tensioning said cable means, and guide means for guiding the movement of said carriage in parallel spaced relation to said shaft, whereby rotation of said shaft will cause centrifugal force to act upon said sides to urge said sides to pivot on the base to open the basket,

and said carriage and yoke are operative to close the basket against a centrifugal force even greater than that which caused the opening of the basket.

References Cited in the file of this patent UNITED STATES PATENTS 729,382 Moore May 26, 1903 830,389 Wells Sept. 4, 1906 1,246,035 B air Nov. 13, 1917 

1. A PULP DRYING DEVICE COMPRISING A ROTATABLY MOUNTED SHAFT, A BASKET HAVING A BASE FIXEDLY MOUNTED ON SAID SHAFT AND A PLURALITY OF FLUID-PERMEABLE SIDES PIVOTED ON SAID BASE, A LINKAGE ELEMENT CONNECTED TO A FREE END OF EACH OF SAID SIDES AND A YOKE SLIDABLY MOUNTED ON SAID SHAFT AND FIXED AGAINST RELATIVE ROTATION THERETO AND CONNECTED TO SAID LINKAGE ELEMENTS AND A POWER-OPERATED CARRIAGE HAVING MEANS ENGAGING SAID YOKE IN JORNALLED RELATION AND GUIDE MEANS FOR SAID CARRIAGE TO GUIDE SAID CARRIAGE RECIPROCABLY TO MOVE SAID YOKE FOR SUCCESSIVELY OPENING SAID SIDES BY A GIVEN CENTRIFUGAL FORCE TO RELEASE DRIED MATERIALS FROM SAID BASKET AND CLOSING SAID SIDES AGAINST SAID GIVEN CENTRIFUGAL FORCE TO PREPARE THE BASKET TO RECEIVE MATERIALS TO BE DRIED BY CENTRIFUGING FLUID THEREFROM THROUGH SAID SIDES. 